Thank you @mozgy and @martinayotte for the help. I'll reboot with the new driver and see if that helps. I couldn't see any other reason that Serial port would cause crashing or fail to print either. Thank you for the link!

I have installed the updated driver, restarted, but still nothing incoming on that serial port. Not crashing anymore, so far, bauds match up. I can upload sketches and the device operates as expected, but it seems like the serial port is blind to the device printing to it. So strange. Sorry, I know it's not ESP related, but I can't debug my ESP code if I can't see serial output. Sad day today. lol

Well, I was able to get some Serial.print output when using a test sketch from the examples section, but it still will not print to serial in my custom sketch. I read about a gcc compiler problem on linux based systems that somehow effects Serial.print. I can't even get consistent results using the example code. One time it prints to serial, the next it doesn't, or the serial.print is intermittent. I'm starting to pull my hair out now. Should I just throw these LoLin NodeMCUs out and buy genuine ones?